(()=>{
   class Person{
       name:string
       sex:string
       age:number
       constructor(name:string,sex:string,age:number){
            this.name = name;
            this.sex = sex;
            this.age  = age;
       }
       sayHi(){
           console.log(`我是${this.name},今年${this.age},是一个${this.sex}`);
       }
   }
   class Student extends Person{
       constructor(name:string,sex:string,age:number){
            super(name,sex,age)
       }
       sayHi(){
           super.sayHi()
       }
   }
   const student = new Student("1","2",3)
   console.log(student)
   student.sayHi()
})()